Transcription profiling of mouse primary splenocytes enriched or depleted of follicular dendritic cells to study the events leading to maturation of follicular dendritic cells and lymphoid germinal centers

Comparison of follicular dendritic cell-enriched versus -depleted splenocytes. Affinity maturation and Ab class switches occur in lymphoid germinal centers (GCs), in which differentiation and maintenance depend on lymphotoxin (LT) signaling and include differentiation of follicular dendritic cells (FDCs). The events leading to FDC and GC maturation are poorly defined. Using several approaches of functional genomics, we enumerated transcripts affected in mice by suppressing LT receptor (LTR) signaling and/or overrepresented in FDC-enriched GC isolates. Protein expression analysis of 3 of 12 genes both enriched in FDCs and down-regulated by LTR signaling suppression validated them as FDC markers. Functional analysis of one of these three, clusterin, suggests a role as an FDC-derived trophic factor for GC B cells. Hence, the set of genes presented in this study includes markers emanating from LTR signaling and transcripts relevant to GC and FDC function.